On the one hand, you’ve got large corporations claiming soy is very healthy and a perfect source of proteins for vegetarians and those with lactose intolerance.
On the other hand, you’ve got numerous little groups claiming soy is not healthy in certain forms (particularly unfermented).
The Good: Soya Health Benefits
Soybean is a source of complete protein (containing all the essential amino acids), it is low in saturated fats, high in fibre. As such, it should be a good substitute for people wishing to avoid meat and lactose. Soy also boasts other health claims such as the one endorsed by the FDA: soy protein lowers the risk of coronary heart disease.
As a result of these health properties, soy has been used in a vast range of products:
- in meat alternatives (tofu, tempeh, vegetarian burgers, vegetarian sausages, vegetarian bacon)
- in dairy alternatives (soy milk, cream, butter, cheese, deserts, soy-based infant formula, ice cream)
The Bad: Why Soya Is So Important … For The Economy
Unfortunately, soy has more properties of a different kind: it is very lucrative.
Soy is lucrative to grow because growers can sell both of the soy sub-products (oil and meal). This is why:
- Soy is now the second most planted crop in the USA, after corn (1).
- The use of genetically-modified soy is wide-spread (herbicide-resistant, fast-grower). In the world’s three largest producing countries, the USA, Brazil and Argentina, about 70-90 % of soybean produced consists of GM varieties (3).
- Large areas of rainforest have given place to soy fields in Brazil (2).
Soy is also extremely lucrative to transform. Considerable value addition occurs at the downstream stages of the production and processing chain. Soy is a big industry ($2.6 billion industry in the USA in 2010)
Consequently, you also find soy in unsuspected places: snacks, cereals, protein powder, soybean oil (often called vegetable oil), margarines. Even if you think you don’t consume soy, you probably are. Refined soya is a hidden ingredient in many refined and pre-packaged foods available on the wider market. It is used to “pad out” such foods – generally people are not even aware that they are eating it. Soy oil, soy lecithin, soy sauce, and soy flour are just a few ingredients that are in many foods available today. It is often hiding in mayonnaise, vegetable broths, shortening and other oils (often called vegetable oils).
The Ugly: How Soya Is Abused And The Potential Consequences On Our Health
It is during World War II that soybeans became important in both North America and Europe chiefly as substitutes for other protein foods and as a source of edible oil.
However in recent years, the virtues of soya in such quantities and forms have been questioned and it was even alleged that soya could have adverse effects such as:
- raising oestrogen levels (oestrogen would occupy receptor sites intended for testosterone causing many development problems in boys – breasts, underdeveloped gonads, lower sperm count, undescended testicles- and earlier puberty for girls leading to infertility problems later and possibly breast cancer)
- interfering with thyroid functions (due to the plant hormones in soya known as isoflavones or phytoestrogens)
- causing allergic responses (due to the widespread use of soy in infant milk, processed food and the possibility of greater allergenicity of genetically modified soy)
To Eat Or Not To Eat Soya?
Haven’t Asian people consumed soya for generations? Surely they should know if it was unsafe?
These are good questions and they cause more controversy. Some claim that Asian people do not in fact eat as much soy as once thought and they mostly eat fermented products (miso, natto, tempeh). Others saying it simply isn’t true.
One of the most factual articles I’ve read about the subject (Nutrition Journal (4)) concludes that, taken at dietary levels (less than 100mg a day), soy neither elicits adverse breast-cancer promoting effects, nor does it improve the prognosis of breast cancer patients.
My conclusion: Unless you’re allergic to soy or receive anti-oestrogen treatment, you should not need to avoid soy (it is a good source of plant protein). However, you should have a balanced varied diet where soy is one element of it, not the key element.
As for soy lecithin which is used in many processed food (it’s cheap for the manufacturers and helps food ‘gel’ together better), should you avoid it?
Well, do you really need all these processed foods anyway???
Obviously there are arguments on both sides, but for those of you in the ‘No’ camp, you might enjoy this video: